hypervisor, vmm: Add support for KVM_SEV_SNP_LAUNCH_UPDATE

Implement the KVM_SEV_SNP_LAUNCH_UPDATE ioctl.

Extend Vm::import_isolated_pages() with a uaddrs parameter carrying
host virtual addresses, which KVM needs, unlike MSHV. Compute uaddrs
from guest memory mappings in the IGVM loader.

Add KVM_SEV_SNP_LAUNCH_UPDATE to the seccomp allowlist.

Co-authored-by: Keith Adler <kadler@cloudflare.com>
Signed-off-by: Keith Adler <kadler@cloudflare.com>
Co-authored-by: Alex Orozco <aorozco@google.com>
Signed-off-by: Alex Orozco <aorozco@google.com>
Signed-off-by: Ruben Hakobyan <hruben@meta.com>

hypervisor/src/vm.rs

@@ -429,6 +429,7 @@ pub trait Vm: Send + Sync + Any {
         _page_type: u32,
         _page_size: u32,
         _pages: &[u64],
+        _uaddrs: &[u64],
     ) -> Result<()> {
         unimplemented!()
     }